Soil testing assemblies

ABSTRACT

An apparatus for securing a soil testing device and other attachments necessary for soil testing near the bottom of a borehole uses a pair of clamps with gripping teeth that interlock with similar gripping teeth in the internal wall of the auger. The lateral movements of the clamps toward the auger are controlled so that the soil testing device is maintained in a proper orientation with respect to the soil sample and to avoid uncontrolled engagements of the clamps with the auger.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on provisional application Ser. No.60/020,228, filed Jun. 18, 1996.

FIELD OF THE INVENTION

This invention relates generally to techniques for testing soil, andparticularly, to clamping assemblies for securing soil testing devicesin a borehole.

BACKGROUND OF THE INVENTION

It is often important to determine properties such as the resistance ofa soil to liquefaction, the degradation characteristics of a soil, thedynamic shear modulus of a soil at low levels of shear deformation, andthe variation in the shear modulus of a soil with shear deformation.Commonly, these soil properties, as well as others, are necessary forthe analysis which predicts the response of a site or foundationstructure system to dynamic loading caused by earthquakes, ocean waves,or mechanical vibrations.

Soil properties may be determined by in situ field tests. For example,the liquefaction resistance of a soil may be determined by a penetrationtest that involves penetrating a closed ended probe into the ground at aslow, controlled rate or driving a cylinder into the ground by violentimpacts. The resistance of the soil to liquefaction is correlated to theresistance of the probe or cylinder to penetration. A technique that canmeasure the resistance of a soil to liquefaction by torsionally excitingthe soil is disclosed in the U.S. Pat. Nos. 4,594,899 and 5,203,824 toRobert Henke and Wanda Henke. In these patents, the illustrated testingdevice includes a pair of concentric open ended cylinders that areinserted into the soil to be tested. A torque may be applied to theinner cylinder and the response of the cylinder and the soil to theapplied torque may be measured by sensors mounted on the inner cylinder.

In such soil tests a borehole is drilled to access the soil sample andthe testing device is lowered down the borehole to test the soil. Thetesting device may be secured to an auger in the borehole. The testdevice may be subjected to substantial applied forces or torques orother reaction forces from the soil. Thus the auger to which the testingdevice is anchored may serve as a reaction means to carry out variousoperations on the testing device.

If the testing device is not properly secured to the auger, the testingdevice may slip from the auger as a result of the reaction forcesproduced by the applied forces or torques on the testing device. Thereis a need for a device that better secures the testing device to theauger.

The testing device should maintain a correct orientation with respect tothe soil sample, even when the testing device is subjected to appliedforces or torques. This is because improper orientation of the testingdevice may cause inaccuracies in test results or damage to the testingdevice.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, a soil testingdevice insertable into a borehole, includes a first external cylinder. Asoil testing device is located inside the cylinder. A clamping elementis connected to the soil testing device. The clamping device is arrangedto extend laterally outwardly to engage said cylinder. The cylinder andthe clamping device have mating surfaces which are textured to preventrelative movement between the device and the cylinder along the lengthof the borehole.

In accordance with another aspect of the present invention, a soiltesting device insertable into a borehole, includes lateral clampsadapted to engage the internal wall. A pair of elements extendingoutwardly beyond said clamps, are adapted to center said clamp framewithin said auger.

In accordance with yet another aspect of the present invention, a soiltesting device includes an auger having an internal wall. A clamp frameis disposed within the auger. A pair of lateral clamps arelongitudinally aligned and disposed exterior to the clamp frame, thelateral clamps adapted to engage the internal wall of the auger. Aplurality of safety rods are attached to the clamp frame, extendingoutwardly from the clamp frame. The safety rods are adapted to controlthe lateral extension of the lateral clamps. A plurality of safety rodbumpers are attached to the safety rods, the bumpers arranged to preventuncontrolled engagement of said lateral clamps with the auger. Aplurality of clamp frame bumpers are attached to the clamp frame, thebumpers arranged to prevent uncontrolled engagement of the lateralclamps with the auger.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial sectional view of one embodiment of the presentinvention suspended within a borehole;

FIG. 2 is an enlarged, vertical cross-sectional view through the lateralclamping assembly shown in FIG. 1;

FIG. 3 is an enlarged cross-sectional view taken generally along theline 3--3 in FIG. 2; and

FIG. 4 corresponds to FIG. 3, but after the clamping assembly has beenexpanded.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawing wherein like reference characters are used forlike parts throughout the several views, a clamping assembly 10, shownin FIG. 1, is suspended in a cylindrical auger 12, in turn in positionwithin a borehole "A". The clamping assembly 10 may be suspended on aline 14 from the surface. A soil testing device 16 is connected to thelateral clamping assembly 10. The soil testing device 16 could be of thetype disclosed in U.S. Pat. Nos. 4,594,899 and 5,203,824, both of whichare hereby expressly incorporated by reference herein. A soil testsample could be taken from the region "B" of the borehole "A"immediately below the auger 12.

The lateral clamping assembly 10 secures the soil testing device 16 inplace near the bottom of the auger 12. The assembly 10 is used toprevent relative movement between the clamping assembly/associatedattachments and the auger in a direction parallel to the longitudinalaxis of the auger 12. Thus, the auger 12 may serve as a reaction meansto support various operations involving a device 16 attached to theclamping assembly 10. For example, the system may be useful inconnection with the penetration of a soil testing device 16 into thesoil "B" and its subsequent rotation.

The clamping assembly 10 includes a clamp frame 18, a pair of sliderbearings 20, a pair of lateral clamps 22 and safety rods 24, as shown inFIG. 2. The slider bearings 20 are threadly mounted on the clamp frame18. The lateral clamps 22 are mounted on the slider bearings 20. Thesoil testing device 16 and other necessary attachments for soil testingmay be attached to the frame 18 from below.

The lateral clamping assembly 10 is supported by the clamp frame 18which connects to the line 14. The frame 18 extends through the centerof assembly 10 and has an opening 28 which threadedly receives thebearings 20. The frame 18 also includes an opening 32 through whichpasses a transversely oriented coil spring 34 retained on studs 36.Likewise, the coil spring 38 is retained by pins 40 and extendstransversely through an opening 42 in the frame 18.

The clamping assembly 10, located inside the auger 12, surrounds theclamp frame 18 and is made up of two generally cylindrical half sections44 and 46, as shown in FIG. 3. The sections 44 and 46 are moveablelaterally outwardly and inwardly with respect to the clamp frame 18.Referring to FIG. 2, the assembly 10 includes the upper sections 48, thelower sections 50 and the bottom sections 52, these sections beingconnected and moveable. In response to internal hydraulic pressureapplied through a connection, not shown, to the space 60 betweensections 50 and the slider bearings 20, sections 44 and 46 extendlaterally outwardly, relative to one another, until they engage theinside surface of the auger 12. When the fluid pressure is released, theelements 44 and 46 return to the position shown in FIG. 3 due to theaction of the springs 34 and 38. Of course, other mechanisms can be usedto expand the assembly 10.

As shown in FIG. 3, the external wall 62 of the lateral clampingassembly 10 is generally cylindrically shaped to match the cylindricalinternal auger 12 wall. The external wall 62 of the assembly 10 includescircumferential ribs 64 which mate with conforming ribs 66 on theinternal wall of the auger 12. In this way, the mating ribs of thelateral clamps and auger interlock thereby providing resistance toslippage of the clamping assembly 10 when force or torque is supplied toa testing device 16 attached to the clamping assembly 10.

The ribs 66 on the internal wall of the auger 12 may extend vertically adistance greater than the vertical height of assembly 10. In this way,there is some freedom in positioning the clamping assembly 10 in theauger 12.

The mounting of lateral clamps 22 on the slider bearings 20 is shown inFIG. 2. As shown in FIG. 2, the slider bearing 20 has an unthreadedcylindrical part 68 and a threaded cylindrical part 70, the unthreadedcylindrical part 68 having a larger diameter than the threadedcylindrical part 70. The threaded cylindrical part 70 mates withthreaded holes 28 in the clamp frame 18. On the unthreaded cylindricalpart 68 of the slider bearing 20 is a slit 74 that runs along thecircumference of the unthreaded cylindrical part 68. The slit 74 securesa lip seal 76 to the slider bearing 20. The seal 76 may be encased in awear-resistant metal ring (not shown).

The lateral clamps 22 are slidably mounted on the slider bearings 20.The seal 76 prevents the assembly 10 from making direct contact with theslider bearing 20, thus allowing the assembly 10 to freely slide in theborehole in the transverse direction. The seals 76 on the sliderbearings sealingly engage the lateral clamps 22 such that an oilenclosure 60 is defined.

The springs 34 and 38 maintain the sections 44 and 46 in the retractedposition, shown in FIGS. 2 and 3, until an applied force overcomes theresistance of the springs 34 and 38, separating the sections 44 and 46from the clamp frame 18, as shown in FIG. 4. The lateral clamps 22 maybe released from the retracted position by hydraulic means which mayinclude feeding pressurized fluid into the enclosure 60, for example.When the lateral clamps 22 are released from the retracted position, thelateral clamps 22 move away from the clamp frame 18 toward the internalwall of the auger 12. The lateral clamps 22 are in an extended positionwhen the ribs 64 on the lateral clamps 22 interlock with the ribs 66 ofthe internal wall of the auger 12. Motion sensors (not shown) may beattached to the clamp assembly 10 to indicate when the lateral clampsshould be released from the retracted position and allowed to engage theinternal wall of the auger 12.

The lateral extension of the lateral clamps 22 is controlled by safetyrods 24. As shown in FIG. 2, the safety rods 24 include safety rodbumpers 82 on one end and threaded portions 84 on the other end. Thethreaded portions 84 of the safety rods 24 mate with threaded holes 86on the clamp frame 18. The safety rods 24 are connected to the clampframe 18 via holes 88 in the lateral clamps 22. The holes 88 havesimilar shapes to the safety rods 24. In this way, the lateral clamps 22move laterally past the rods 24 when sliding from the retracted positionat the clamp frame 18 to the extended position at the internal wall ofthe auger 12.

The safety rod bumpers 82 may include a necked down, threaded portion 83which threadedly engages the rest of the safety rod 24. The safety rods24 are mounted in pairs on opposite sides of the clamp frame 18. Thesafety rod heads 25 are spaced from the clamps 22 in such a way that thelateral clamps 22 are prevented from extending too far outwardly. Theabutting surfaces 102 and 104 contact to stop the outward extension ofthe clamps 22.

As shown in FIG. 2, safety rod bumpers 82, have a curved outward surface93, and may be made of Delrin. The safety rod bumpers 82 extendoutwardly from the lateral clamps 22 when the lateral clamps 22 are inthe retracted position. In this way, the lateral clamps 22 are preventedfrom engaging the auger 12, for example, before the lateral clamps 22are released to engage the internal wall of the auger 12. The safety rodbumpers 82 are hidden in the slots 95 in the lateral clamps 22 when thelateral clamps 22 have engaged the internal wall of the auger 12.

As shown in FIG. 2, clamp frame bumpers 92 are fitted to the channels 94at the base 96 of the clamp frame 18. The clamp frame bumpers 92 assistin preventing the lateral clamps 22 from engaging the internal wall ofthe auger 12 in an uncontrolled manner. The bumper 92 may be made ofDelrin as well.

The clamping assembly 10 is generally used to secure a soil testingdevice near the bottom of an auger 12 as follows. Initially, the lateralclamps 22 are at a retracted position, secured to the clamp frame 18. Asoil testing device 16 is attached to the base 96 of the clamp frame 18.The clamping assembly 10 with the soil testing device is lowered by awireline 14, or any other appropriate means, into an auger 12 in aborehole "A". The springs 34 and 38 maintain the lateral clamps in aretracted position as the clamping assembly 10 is lowered.

When the clamping assembly 10 is in position, the lateral clamps 22,which may be hydraulically actuated, are released from the retractedposition, shown in FIG. 3, and allowed to move toward the internal wallof the auger 12, as shown in FIG. 4. The slider bearings 20 and thesafety rods 24 control the movement of the lateral clamps 22 in alateral direction. The lateral clamps 22 engage the internal wall of theauger 12 by interlocking the ribs 64 on its external wall with the ribs66 on the internal wall of the auger 12. Substantial force can beapplied to the clamping assembly 10 to ascertain that the lateral clamps22 are fully engaged to the internal wall of the auger 12. When theclamp frame 18 is ready to be released, the extending mechanism isreversed and the springs 34 and 38 return the lateral clamps 22 to theretracted position, while the hydraulic pressure is released from thepassage 60.

While the present invention has been described with respect to apreferred embodiment, those skilled in the art will appreciate numerousmodifications and variations therefrom. The appended claims are intendedto cover all such modifications and variations which occur to one ofordinary skill in the art.

What is claimed is:
 1. A soil testing device insertable into a borehole,comprising:a first external cylinder; a soil testing device locatedinside said cylinder; and a clamping device connected to said soiltesting device, said clamping device arranged to extend laterallyoutwardly to engage said cylinder, said cylinder and said clampingdevice having mating surfaces which are textured to prevent relativemovement between said device and said cylinder along the length of theborehole, wherein the longitudinal extent of said textured, matingsurface on said cylinder is greater than the longitudinal extent of saidclamping device, said clamping device and said cylinder being configuredsuch that said clamping device can engage said cylinder at a pluralityof spaced apart locations along the length of said cylinder.
 2. Thedevice of claim 1, wherein said cylinder and said clamping element havemating circumferential ribs.
 3. The device of claim 1, including amechanism to laterally extend said clamping element to engage saidcylinder.
 4. A soil testing device insertable into a borehole,comprising:a soil testing device; a plurality of clamping devicesadapted to releasably engage the borehole, wherein said clamping devicesare laterally extendible and retractable; and an element extendingoutwardly beyond each clamping device when said clamping devices are notengaging said borehole wherein said element is arranged to control theamount of lateral extension of said clamping devices, said elementincluding a metal shaft threadedly secured to a hard plastic bumper. 5.A soil testing device comprising:a soil drilling device having aninternal wall; a soil testing device located in said soil drillingdevice; a clamp frame attached to said soil testing device; a pluralityof clamping devices longitudinally aligned and disposed on the exteriorto said clamp frame, said clamping devices adapted to releasably engagethe internal wall of said drilling device; a plurality of safety rodsattached to said clamp frame and extending outwardly from said clampframe, said safety rods adapted to control the lateral extension of saidclamping devices; and a plurality of bumpers arranged to preventuncontrolled engagement of said clamping devices with said soil drillingdevice.
 6. The soil testing device of claim 5, wherein said bumpersextend outwardly from said clamping devices when said clamping devicesare in a retracted position.
 7. The soil testing device of claim 5,including a plurality of clamp frame bumpers attached to said clampframe, said clamp frame bumpers arranged to prevent uncontrolledengagement of said clamping devices with said drilling device, whereinsaid clamp frame bumpers extend outwardly with respect to said clampingdevices when said clamping devices are in a retracted position.
 8. Thesoil testing device of claim 5, wherein said bumpers are disposed withinsaid clamping devices when said clamping devices are extended to engagethe internal wall of said soil drilling device.
 9. The soil testingdevice of claim 7, wherein said clamp frame bumpers are disposedinterior to said clamping devices when said clamping devices areextended to engage the internal wall of said drilling device.
 10. Amethod of testing soil, comprising the steps of:lowering a soil testingdevice into a lined borehole; controlling the lateral position of saiddevice using transversely oriented bumpers; and, extending clampingdevices laterally outwardly to engage said liner borehole such thattextured surfaces on said lined borehole and said clamping devicesinterlock.
 11. The method of claim 10, including the step of using saidbumpers to control the extent of outward extension of said clampingdevices.
 12. The method of claim 10, including the step of forming saidlined borehole using an drilling device.